1. Field of the Invention
The present invention relates to an effect generating system for an electronic musical instrument which provides both vibrato and glide effects. The effects are added, one at a time, to musical tones being generated. More particularly the inventive effect generating system eliminates an unnatural effect from the generated musical tones which is caused by a discontinuity in operation between glide and vibrato performances at the time of switchover from the former to the latter.
2. Description of the Prior Art
In conventional electronic musical instruments equipped with function of producing the vibrato and glide effects, in the case of generating these effects, when both vibrato modulation data indicated by 1 in FIG. 1(a) and glide modulation data indicated by 2 in FIG. 1(a) are simultaneously provided, frequency is carried out by a signal obtained by adding them as shown in FIG. 1(b), or the glide effect is introduced interrupting the vibrato effect as shown in FIG. 1(c). In the electronic musical instrument which can not provide both effects at the same time, such a signal as shown in FIG. 1(c) is obtained. The former method calls for the provision of means for adding together the vibrato modulation data and the glide modulation data but no particular effect is obtained. The latter method presents a problem in that it creates a feeling of unnaturalness in switching over the glide effect to the vibrato effect. That is to say, in the case of the latter method, when changed over from the glide performance, the vibrato performance that has been interrupted for providing the glide effect is suddenly started, giving the listener an abrupt and unnatural impression.